Alcohol effects on human risk taking

Abstract

Rationale

Despite a well-established relationship between alcohol and risky behavior in the natural environment, laboratory investigations have not reliably shown acute alcohol effects on human risk-taking.

Objectives

The present study was designed to demonstrate a dose-response relationship between acute alcohol administration and human risk taking. Further, this investigation sought to delineate behavioral mechanisms that may be involved in alcohol-induced changes in the probability of risky behavior.

Methods

Using a laboratory measure of risk taking designed to address acute drug effects, 16 adults were administered placebo, 0.2, 0.4, and 0.8 g/kg alcohol in a within-subject repeated measures experimental design. The risk-taking task presented subjects with a choice between two response options operationally defined as risky and non-risky. Data analyses examined: breath alcohol level (BAL), subjective effects, response rates, distribution of choices between the risky and non-risky option, and trial-by-trial probabilities of making losing and winning risky responses.

Results

The alcohol administration produced the expected changes in BAL, subjective effects, and response rate. Alcohol dose-dependently increased selection of the risky response option, and at the 0.8 g/kg dose, increased the probability of making consecutive losing risky responses following a gain on the risky response option.

Conclusions

Acute alcohol administration can produce measurable changes in human risk-taking under laboratory conditions. Shifts in trial-by-trial response probabilities suggest insensitivity to past rewards and more recent losses when intoxicated, an outcome consistent with previous studies. This shift in sensitivity to consequences is a possible mechanism in alcohol-induced changes in risk taking.

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Acknowledgements

This research was supported by NIDA grant DA R01 15392. We thank Dr. Kim Fromme for generously providing psychometric instruments, and Jennifer Sharon, Sally Chee, and Ehren Bradbury for their assistance in conducting the experiments.